Metabolic impact of shivering during therapeutic temperature modulation: the Bedside Shivering Assessment Scale.
OBJECTIVE
Therapeutic temperature modulation is widely used in neurocritical care but commonly causes shivering, which can hamper the cooling process and result in increases in systemic metabolism. We sought to validate a grading scale to assist in the monitoring and control of shivering.


METHODS
A simple 4-point Bedside Shivering Assessment Scale was validated against continuous assessments of resting energy expenditure, oxygen consumption, and carbon dioxide production as measured by indirect calorimetry. Therapeutic temperature modulation for fever control or the induction of hypothermia was achieved with the use of a surface or endovascular device. Expected energy expenditure was calculated using the Harris-Benedict equation. A hypermetabolic index was calculated from the ratio of resting of energy expenditure to energy expenditure.


RESULTS
Fifty consecutive cerebrovascular patients underwent indirect calorimetry between January 2006 and June 2007. Fifty-six percent were women, and mean age 63+/-16 years. The majority underwent fever control (n=40 [80%]) with a surface cooling device (n=44 [87%]) and had signs of shivering (Bedside Shivering Assessment Scale >0, 64% [n=34 of 50]). Low serum magnesium was independently associated with the presence of shivering (Bedside Shivering Assessment Scale >0; OR, 6.8; 95% CI, 1.7 to 28.0; P=0.01). The Bedside Shivering Assessment Scale was independently associated with the hypermetabolic index (W=16.3, P<0.001), oxygen consumption (W=26.3, P<0.001), resting energy expenditure (W=27.2, P<0.001), and carbon dioxide production (W=18.2, P<0.001) with a high level of interobserver reliability (kappa(w)=0.84, 95% CI, 0.81 to 0.86).


CONCLUSIONS
The Bedside Shivering Assessment Scale is a simple and reliable tool for evaluating the metabolic stress of shivering.
Badjatia
Neeraj
N
Departments of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA. nbadjatia@neuro.columbia.edu
Strongilis
Evangelia
E
Gordon
Errol
E
Prescutti
Mary
M
Fernandez
Luis
L
Fernandez
Andres
A
Buitrago
Manuel
M
Schmidt
J Michael
JM
Ostapkovich
Noeleen D
ND
Mayer
Stephan A
SA
D000368:Aged; D000886:Anthropometry; D001481:Basal Metabolism; D002153:Calorimetry, Indirect; D002245:Carbon Dioxide / Q000378:metabolism; D002543:Cerebral Hemorrhage / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D002544:Cerebral Infarction / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D003422:Critical Care / Q000379:methods*; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology / Q000627:therapeutic use; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D019095:Point-of-Care Systems; D011446:Prospective Studies; D012720:Severity of Illness Index; D012768:Shivering / Q000187:drug effects / Q000502:physiology*; D013345:Subarachnoid Hemorrhage / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*
D006993:Hypnotics and Sedatives; D002245:Carbon Dioxide